Wondering how much potassium is in your edamame snack, tofu stir-fry, or tempeh bowl? The Soy Potassium Calculator gives you a fast, practical estimate using standard USDA food-composition values. Pick a soy product, enter your portion size, and the tool converts it into milligrams of potassium plus a percentage of your chosen daily reference intake.
This calculator is built for anyone tracking potassium for sports nutrition, kidney-friendly meal planning, or everyday micronutrient balance. Because soy foods vary widely — edamame and mature soybeans are rich in potassium, while tofu and soy milk contain less — the tool lets you compare different products side by side in seconds. Cooked, boiled, steamed, and processed soy items are all covered.
🧮 Soy Potassium Calculator
Estimate the potassium content of edamame, tofu, tempeh, natto, soy milk, and other soy foods.
1. Choose soy product
2. Enter amount
Cup weights are approximate; a kitchen scale gives the most accurate result.
3. Daily value reference
Step-by-Step Guide
Using this calculator takes less than a minute. First, pick the soy product you actually have in front of you — edamame, mature soybeans, tofu, tempeh, natto, soy milk, or soy flour. Each item is linked to a standard potassium value per 100 grams taken from USDA food-composition data.
- Select the soy product from the dropdown. The potassium value updates behind the scenes.
- Enter your portion size in grams. If your label lists ounces, switch the unit dropdown or type the ounce value and the tool converts automatically. A small kitchen scale gives the most reliable portion weight.
- Choose the daily reference value that matches your goal. The default is the FDA Daily Value of 4,700 mg; 3,500 mg reflects UK/European guidance, and 2,600 mg can be a useful planning target for lower-potassium dietary patterns.
- Press Calculate. The result box shows total potassium and the percentage of your chosen reference, with a breakdown of each step.
If you want to check a portion that is cooked or measured after boiling, use the cooked weight rather than the raw weight. Soybeans absorb a lot of liquid and their potassium concentration changes after cooking.
How the Calculation Works
Potassium values in the calculator come from the USDA FoodData Central database and are expressed as milligrams per 100 grams of the edible portion. The tool uses two simple formulas:
Total potassium (mg) = portion weight (g) × potassium per 100 g ÷ 100
Daily value percentage = total potassium (mg) ÷ chosen reference (mg) × 100
For example, a 155-gram cup of boiled shelled edamame contains about 436 mg of potassium per 100 g. The calculation is 155 × 436 ÷ 100 = 675.8 mg. Against the FDA reference of 4,700 mg, that is 675.8 ÷ 4,700 × 100 = 14.4% of the daily value. If you normally eat a 100-gram portion of tempeh, you get 412 mg, or 8.8% DV.
Potassium Reference Values for Soy Products
The table below summarizes common soy-based foods. Use the mg per 100 g column if you weigh your food; the per-cup column is included as a convenience because many recipes measure soy products in cups.
| Soy product | mg potassium / 100 g | 1-cup weight (g) | mg potassium / cup |
|---|---|---|---|
| Edamame, boiled shelled | 436 | 155 | 676 |
| Soybeans, mature cooked | 515 | 172 | 886 |
| Tempeh | 412 | 166 | 684 |
| Natto | 660 | 175 | 1,155 |
| Firm tofu | 121 | 252 | 305 |
| Soft tofu | 135 | 248 | 335 |
| Soy milk | 118 | 243 | 287 |
| Soy flour, full-fat roasted | 2,387 | 84 | 2,005 |
All values are approximate. Different brands, fortification, and cooking methods can shift potassium by 10–20%.
Tips for Accurate Potassium Tracking
- Weigh the food after cooking or steaming unless a recipe states otherwise.
- Read the nutrition facts label if you use a branded product, especially for fortified soy milk or tofu made with calcium sulfate; the label is more specific than a generic database value.
- Remember that boiling can leach potassium into the cooking water, so drained boiled soy products may have slightly less than the listed value.
- If you are tracking other plant sources of potassium, the almond potassium calculator can help you tally that source too.
Frequently Asked Questions
Is soy high in potassium? It depends on the form. Mature soybeans, edamame, tempeh, and natto are genuinely rich in potassium. Tofu is low-to-moderate because the curd retains only part of the soybean’s minerals, and soy milk is comparatively low.
What is the difference between 4,700 mg and 3,500 mg? The FDA uses 4,700 mg as the Daily Value for food labels in the United States. The UK and the European Food Safety Authority commonly cite 3,500 mg per day for adults. People with specific medical conditions may receive different targets from their clinician.
Can I compare this to other potassium calculators? Yes. If you also eat seeds, the chia potassium calculator is a useful companion for plant-based potassium tracking.
Does cooking change the result? Yes. Soybeans cooked from dry absorb water, so a cup of cooked beans contains less potassium per 100 g than dry raw soybeans. Always match your portion weight to the product state described in the calculator.
Real-World Applications
This calculator is useful for anyone filling a high-potassium nutrition plan, athletes who want to replace electrolytes after training, or people reviewing their micronutrient intake. Vegetarians and vegans often use soy products as a protein staple; knowing their potassium load makes it easier to balance the rest of the day’s foods. The results also help with meal prep: you can calculate a batch of tempeh or a tofu scramble and divide it by the number of servings.
For more background on potassium requirements and dietary sources, see the NIH Office of Dietary Supplements potassium fact sheet.